A £2.2bn pipeline that will deliver a million barrels of crude oil a day to the Mediterranean Sea, and is set to become a vital gateway for central Asian energy resources to the west, opened yesterday.

The Baku-Tbilisi-Ceyhan (BTC) pipeline will run for 1,100 miles from the Azerbaijani capital, through Georgia to the Turkish port, and through two of the most politically turbulent countries in the region.

Washington, uncomfortable at its reliance on oil from the Middle East, has long sought the BTC as a bridge for the massive energy resources of Kazakhstan, a country the size of western Europe.

The pipeline has stoked controversy on several fronts.

Apart from the environmental hazards (it passes close to a national park in Georgia and traverses highly seismic landscape throughout its route), the pipeline has brought western powers into partnership with governments with suspect human rights records.

Presidents Ilham Aliev of Azerbaijan, Ahmet Sezer of Turkey, Mikhail Saakashvilli of Georgia and Kazakhstan's Nursaltan Nazarbayev attended the inauguration ceremony yesterday at the Sangachal terminal, 25 miles south of Baku.

They were joined by the US energy secretary, Samuel Bodnam, and Lord Browne, head of British Petroleum, the largest shareholder in the project, with a 30.1% stake.

Mr Aliev opened the tap permitting the first oil into his country's section of the pipeline, named after his father, Heydar Aliev, whom he succeeded after an election marred by violence and fraud allegations. His government has a 25% stake in the project that he expects to help the economy grow by 18%.

"Some doubted the feasibility of the Baku-Tbilisi-Ceyhan project, while others tried to raise obstacles," Interfax quoted him as saying. "The union of Azerbaijan, Turkey, Georgia and the United States ... made this a reality."

Oil from the pipeline is not expected at the Turkish port of Ceyhan until August 15, and will supply 1% of global demand. Many analysts see greater potential for the BTC as a conduit for central Asian oil, principally from Kazakhstan. Mr Nazarbayev unveiled plans this week to link the western Kazakh oil port of Aktau to the BTC.

The Bush administration first recognised the pipeline's potential in May 2001, when an energy policy review spearheaded by the vice-president, Dick Cheney, said the Kashagan oilfield in Kazakhstan was capable of exporting 2.6m barrels a day if pipelines like the BTC were operational.

The report recommended Mr Bush to order the departments of state and energy to "establish the commercial conditions" to facilitate Kazakh exports via the BTC. Since then the US has increased its military assistance to the authoritarian Mr Aliev, while at the same time supporting a pro-western revolution in Georgia.

"This is confirmation of American double-standards - supporting regimes that are authoritarian, but part of their energy package," said the analyst Lilya Shevtsova of the Carnegie Endowment, in Moscow. She said the BTC also gave Azerbaijan and Kazakhstan independence from Russia, upon whose pipelines they had previously relied to export their oil.

The move away from the Russian pipelines will also benefit Washington, which is keen to immunise its energy supplies from possible friction with Russia and Iran.

The US is also expected to increase its military presence in Azerbaijan, which will further rile Moscow.